Tailored Dielectric Properties and Tunability of Lead Free Relaxor Ba(Zr_xTi_{1 − x})O₃:MgO Composites

Abstract

Among the environmental friendly lead free perovskite ferroelectrics, Barium Zirconate Titanate, Ba(Zr _x Ti _{1 − x} )O ₃ (BZT) compositions have attracted considerable attentions for the potential tunable microwave device applications such as tunable filters, resonators, phase shifters, antennas etc. To further enhance the suitability of BZT compositions and tailoring their dielectric properties, MgO has been introduced to fabricate the Ba(Zr _x Ti _{1 − x} )O ₃ :MgO composites for optimum device applications. DC electric field dependence of dielectric behavior of the ceramic composites has been studied in the temperature range from 300 K to 11 K for the tunable dielectric devices. The results have been analyzed in relation to the tunability (%) and the figure of merit (K-factor) of the tunable dielectric materials. Manipulating the Zr:Ti concentration and optimizing the percentage of MgO in BZT:MgO composites the tunable dielectric properties at desired temperature can be tailored to make it useful in an array of different tunable microwave applications.

Keywords:

• Relaxor
• composite
• tunability
• environmental friendly
• microwave device

Acknowledgments

This work is supported by the grants from the Division of Materials Research of the National Science Foundation (NSF) under Grant No. DMR-0407462 and CMS-0528873.